Folia biologica et geologica

Plant growth promoting microorganisms: a promising tool for improving forest tree seedlings survival (a review)

Tina Unuk Nahberger — Wed, 05 Nov 2025 00:00:00 +0100

Severe drought events and increasingly frequent large-scale forest disturbances can lead to a significant and irreversible decline in the natural regeneration of various forest tree species. Extensive research is being carried out to develop strategies to help plants cope with the increasing stress. However, most of these technologies are costly and time-consuming, so the application of plant growth-promoting microorganisms (PGPMs) appears to be an easy-to-use and efficient method to alleviate abiotic and biotic stress in plants. PGPM inoculants are a sustainable alternative strategy to not only alleviate stress through various mechanisms, but also to promote plant growth and development. Previous studies have revealed a wide range of PGPM genera that colonise plant roots and enhance the ability of plants to cope with abiotic and biotic stress in agriculture. However, records on the potential benefits of PGPMs in forest seedlings are still sparse, with only a few reports and mostly isolated strains from the genera Pinus, Quercus, Abies and Picea. This review addresses the current knowledge on plant growth-promoting mechanisms and provides an overview of isolated microorganisms with proven plant growth-promoting mechanisms from different forest tree species.

Viromics analysis of RNA viruses in samples from the Triglav and Skuta glacier

Wed, 05 Nov 2025 00:00:00 +0100

Despite low temperatures and limited availability of water and nutrients, there is a high level of biological diversity hidden in the glaciers. Glacial microbial ecosystems are primarily composed of bacteria, algae, and fungi. However, knowledge about viruses in these extreme environments remains limited. To address this gap, we conducted virome analysis on two Slovenian glaciers: Triglavski ledenik (Triglav glacier) and ledenik pod Skuto (glacier below Skuta). From concentrated samples of melted glacial ice, we isolated ribonucleic acids (RNA), amplified them using random oligonucleotide primers, and performed untargeted sequencing using the Illumina platform. Through bioinformatic analyses, we identified viral sequences in the obtained data and classified them taxonomically. As expected, the proportion of reads classified as viral was low. Despite focusing on the description of RNA viral diversity, the most frequently detected viral reads in all glacier samples were those belonging to DNA bacteriophages, classified within the realm Duplodnaviria. Most of the viral sequences discovered in the Slovenian glacier samples showed low identity with known viral sequences in databases, indicating the presence of numerous novel viral species. Longer assembled viral sequences likely represent complete genomes of newly discovered RNA viruses (e.g., sequences related to toti-like and picorna-like virus groups). For these sequences, phylogenetic analyses revealed their closest known viral relatives and potential host organisms. This study represents the first insight into the presence of viruses in Slovenian glacier environments and reveals a large, previously unexplored diversity of these biological entities.

The Extent of labour and costs of forest restoration with planting, sowing, and protection measures against game damages in Slovenia in the period 2007-2020

Gregor Božič, Marijana Vidrih Minić, Boris Rantaša, Andrej Breznikar — Wed, 05 Nov 2025 00:00:00 +0100

We analysed the scope and costs of forest restoration with planting and sowing in Slovenia for the period 2007 – 2020, which was carried out by the Slovenian Forest Service (SFS). In the 14-year period, forest restoration by planting seedlings was carried out on 5,353 ha of forest areas, the soil preparation for restoration with planting and sowing measure on 3,489 ha, and the sowing measure on 457 ha. In total, 0.5% of the area of managed forests was restored in Slovenia, which on average means 0.04% of the area of managed forests per year. 61% of the forest areas restored with planting (approximately 3,300 hectares of forest) were protected against game damage. During this period, €9,457,562 was spent on seedlings, of which 66% for broadleaves and 34% for conifers. Within the scope of forest restoration with planting, 6,176,099 broadleaf seedlings (51%) and 5,913,388 conifer seedlings (49%) were planted, for a total of 12,089,487 trees. In the period from 2007 to 2020, €33,595,188 was spent on artificial forest restoration measures across the entire territory of Slovenia, with the largest portion going to planting (53%) and protection against game damage (42%), followed by soil preparation (4%) and sowing (1%). In the period under review, the average purchase price (value) of a classic bare-root seedling was €1.19 for broadleaves and €0.52 for conifers, while the average value of a container seedling was €1.96 for broadleaves and €1.67 for conifers. A comparison between the per-hectare restoration costs incurred with planting and the costs incurred with sowing for 14 forest managemet regions in the studied period shows that the cost per hectare for the planting measure is significantly higher (€6,187/ha) than the cost per hectare for the sowing measure (€1,036/ha).